Emergency power supply



FIG. 1 is a front view of an emergency power supply, showing my new design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a bottom plan view thereof;

FIG. 4 is a rear plan view thereof;

FIG. 5 is a left plan view thereof;

FIG. 6 is a right plan view thereof; and,

FIG. 7 is a perspective view thereof.

The broken lines in the drawings depict portions of the emergency power supply that form no part of the claimed design. 

CLAIM The ornamental design for an emergency power supply, as shown and described. 